Viewing Memory as a Unified I/O Cache
A key role of the I/O system is to manage the page/block cache for performance and reliability.
tracking cache contents and managing page/block sharing
choreographing movement to/from external storage
balancing competing uses of memory
Modern systems attempt to balance memory usage between the VM system and the file cache.
Grow the file cache for file-intensive workloads.
Grow the VM page cache for memory-intensive workloads.
Support a consistent view of files across different style of access.